NuAire Labgard NU-430-400, Operation & Maintenance Manual

Page: 39 / 99

OM0228 Page 39 of 99
February/2014
7.3 HEPA Filter/Motor Replacement
The HEPA Filters under normal usage and barring an accident (a puncture), do not need replacement until the exhaust
volume cannot be maintained or the access inflow velocity cannot be maintained at 100 LFPM (min.) .51 m/s). This may
permit the average downflow velocity to be as low as 55 LFPM (.28 m/s) as long as no point falls below 20 percent of the
average downflow velocity.
The HEPA Filters should not be replaced until the entire cabinet has been decontaminated or known to be biologically
"clean". Constant pressure spring ‐ type clamps are used to hold the exhaust filter tightly in place to counteract seal
relaxation, while the supply filter employs NuAire's HEPEX pressure plenum. USE ONLY REPLACEMENT FILTERS OF THE
SAME RATED FLOW AND SIZE AS ORIGINALLY INSTALLED, TO INSURE PROPER AIRFLOW BALANCE CAN BE ACHIEVED.
It is not always necessary to replace both the supply and exhaust filters at the same time. In fact, it is highly likely that the
exhaust filter will need replacement far more often than the supply filter, due to (1) the larger volume of air passing
through it, (2) it’s much smaller size, and (3) the capability of the exhaust system.
7.3.1 Supply Filter Replacement (see Drawing BCD ‐ 05659)
Disconnect electrical power from the cabinet before attempting any maintenance action.
Step 1: Remove screws at each upper side of the control center and allow the control center to rotate down,
resting on the safety straps. Second, remove the front decorative panel, which is held into position by (3)
knurled nuts on the top edge and (6) knurled screws on the front.
Step 2: Place sliding window into lowest position and remove front filter panel, which is held into position by
Phillips pan head screws. Once the screws are removed, remove the panel.
NOTE: Screws are used in lieu of acorn nuts, and lock washers.
The screws have O ‐ rings and should be replaced if damaged or badly deformed.
Step 3: Remove blower access panel, which is held into position by 1/4 ‐ 20 acorn nuts. Once the acorn nuts are
removed, remove the panel.
The interior of the cabinet is now fully exposed for replacement of the filter.
Step 4: To remove the supply filter:
a. Unlatch the three filter clamps. (In front of the supply HEPA filter) The clamps provide very high
tension and may require mechanical assistance to unfasten. Keep finger and hands clear when
releasing!
b. Loosen three black hand knobs (about 3 turns) in back of permanent plenum.
c. Lift the permanent plenum and hold up with wire strap.
d. Carefully remove the supply filter.
DIRECT EXPOSURE SHOULD BE AVOIDED, EVEN THOUGH THE FILTER
IS IN AN UNCONTAMINATED PLENUM .
Step 5: To install the supply filter, simply reverse the procedure outlined in the steps above.
NOTE: WHEN INSTALLING NEW FILTERS, USE ONLY FILTERS OF THE SAME RATED FLOW AND
SIZE AS ORIGINALLY INSTALLED .
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CAUTION
!
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